by Kev Geoghegan
Radio 1 music reporter
Foals will headline the NME stage
Foals, Glasvegas and Dizzee Rascal are among the artists playing the second annual Underage festival in London.
7,500 teenagers are expected at the event in London's Victoria Park.
Last year's festival was hailed a massive success, with NME naming founder, 16-year-old Sam Kilcoyne in a list of music innovators.
He told Newsbeat: "The biggest lesson we learned from last year is that we need more toilets."
Kilcoyne is better placed to start a music festival than most teenagers. His dad, Barry Smith, was in 90s electroclash artists Add N to (X).
He admitted that this time around, it has been easier to organise.
He said: "This year we know what to anticipate and booking bands has been a lot easier because we know what we like."
The festival operates under a strict entrance policy, catering to under 19 year olds only. Some of the bands playing will be the oldest people on the site.
There is also a no drinks policy and Kilcoyne said he has been working closely with Tower Hamlets council and the police.
He said: "We have a couple of search tents but we had no problems last year. There is also a big police presence outside of the fence.
"If anyone looks suspicious, obviously they will be searched."
With tickets increased by 2,500 to 7,500 Kilcoyne is aware that the media's gaze will be firmly fixed on the festival, albeit from a respectable distance.
Glasvegas release their debut album on 8 September
He said: "Well it's one day in the year when none of the media can get in and monitor us.
It's just one day when teenagers can get away from their parents and have fun and listen to music."
At a time when UK festivals face increasing criticism among music fans for corporate sponsorship, the organisers insist they want to keep branding to a minimum inside the event.
But if the festival continues to expand and costs increase, bigger sponsors are surely inevitable.
Kilcoyne said: "It sucks, you get that everywhere in England. I think 7,000 people is big enough for us, to be honest."
Two bands have been forced to cancel appearances at the festival. The Horrors and Mystery Jets - who pulled out earlier this week.